/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.spark.sql.catalyst.expressions

import java.util.Random

import org.apache.spark.sql.types.{DataType, DoubleType}


case object Rand extends LeafExpression {
  override def dataType: DataType = DoubleType
  override def nullable: Boolean = false

  private[this] lazy val rand = new Random

  override def eval(input: Row = null): EvaluatedType = {
    rand.nextDouble().asInstanceOf[EvaluatedType]
  }

  override def toString: String = "RAND()"
}
